So I decided to brew up a dry stout and attempt to do a fast/forced fermentation (FFT) on ~8oz (enough to take a hydrometer reading). That was Friday. Fast forward to yesterday and today — the FFT has finished fermenting while the main fermentation is continuing to bubble away. I check the FG on FFT sample...and it's 1.020 or a 57% apparent attenuation! (OG was 1.048) That's more than 8 points from what I expected (1.012). For those of you who have conducted FFT, how accurate is the final gravity to the real thing?
Just for reference my mash schedule was 152/153 for 90 minutes with a 10 minute mashout around 165. (Higher mash temp to compensate for US-05's higher attenuation.) The grain build was based around the BYO's dry irish stout recipe with pale chocolate malt substituted for the chocolate malt and a half-ounce of Dehusked Carafa II for color.
Just for reference my mash schedule was 152/153 for 90 minutes with a 10 minute mashout around 165. (Higher mash temp to compensate for US-05's higher attenuation.) The grain build was based around the BYO's dry irish stout recipe with pale chocolate malt substituted for the chocolate malt and a half-ounce of Dehusked Carafa II for color.